U.S. patent application number 12/513694 was filed with the patent office on 2011-05-26 for construction method and construction apparatus for offshore wind turbine generator.
This patent application is currently assigned to Mitsubish Heavy Industies, Ltd.. Invention is credited to Tomohiro Numajiri.
Application Number | 20110119889 12/513694 |
Document ID | / |
Family ID | 41720932 |
Filed Date | 2011-05-26 |
United States Patent
Application |
20110119889 |
Kind Code |
A1 |
Numajiri; Tomohiro |
May 26, 2011 |
CONSTRUCTION METHOD AND CONSTRUCTION APPARATUS FOR OFFSHORE WIND
TURBINE GENERATOR
Abstract
Provided is a construction apparatus for safe and smooth
construction of a floating offshore wind turbine generator in deep
sea. The construction apparatus for constructing the offshore wind
turbine generator with a crane ship includes a guide member
attached to the crane ship in a work position perpendicular thereto
such that a bottom end of the guide member is disposed under the
sea and at least one pair of arm units that include grippers
capable of holding and releasing a tower member divided into a
plurality of segments in an axial direction and that slide along
the guide member.
Inventors: |
Numajiri; Tomohiro;
(Nagasaki, JP) |
Assignee: |
Mitsubish Heavy Industies,
Ltd.
Tokyo
JP
|
Family ID: |
41720932 |
Appl. No.: |
12/513694 |
Filed: |
August 28, 2008 |
PCT Filed: |
August 28, 2008 |
PCT NO: |
PCT/JP2008/065396 |
371 Date: |
June 2, 2009 |
Current U.S.
Class: |
29/428 ;
269/86 |
Current CPC
Class: |
F03D 13/10 20160501;
B66C 23/52 20130101; B66C 23/185 20130101; F05B 2240/95 20130101;
B63B 27/16 20130101; Y02E 10/721 20130101; Y02E 10/727 20130101;
B63B 27/10 20130101; F05B 2230/6102 20130101; Y10T 29/49826
20150115; Y02P 70/50 20151101; B63B 35/003 20130101; Y02E 10/72
20130101; Y02P 70/523 20151101 |
Class at
Publication: |
29/428 ;
269/86 |
International
Class: |
B23P 11/00 20060101
B23P011/00; B63B 35/00 20060101 B63B035/00 |
Claims
1. A construction apparatus for constructing a floating offshore
wind turbine generator with a crane ship, the apparatus comprising:
a guide member attached to the crane ship in a work position
perpendicular thereto such that a bottom end of the guide member is
disposed under the sea; and at least one pair of arm units that
include grippers capable of holding and releasing a tower member
divided into a plurality of segments in an axial direction and that
slide along the guide member.
2. The construction apparatus for an offshore wind turbine
generator according to claim 1, wherein the guide member is
attached to the crane ship so as to be rotatable between a sailing
position parallel to the crane ship and the work position
perpendicular thereto.
3. The construction apparatus for an offshore wind turbine
generator according to claim 1, wherein the guide member has an
axially sliding mechanism and/or an extension/retraction mechanism
capable of changing the length in the axial direction.
4. The construction apparatus for an offshore wind turbine
generator according to claim 1, wherein the arm units include a
plurality of sets of grippers whose distance from each other in the
axial direction is changeable.
5. A construction method for constructing a floating offshore wind
turbine generator with a crane ship, wherein the offshore wind
turbine generator is constructed using the construction apparatus
according to claim 1 such that the tower member is joined to the
crane ship.
6. Maintenance equipment for maintaining a floating offshore wind
turbine generator with a crane ship, the equipment comprising: a
guide member attached to the crane ship in a work position
perpendicular thereto such that a bottom end of the guide member is
disposed under the sea; and at least one pair of arm units that
include grippers capable of holding and releasing a tower member
divided into a plurality of segments in an axial direction and that
slide along the guide member.
7. The maintenance equipment for an offshore wind turbine generator
according to claim 6, wherein the guide member is attached to the
crane ship so as to be rotatable between a sailing position
parallel thereto and the work position perpendicular thereto.
8. The maintenance equipment for an offshore wind turbine generator
according to claim 6, wherein the guide member has an axially
sliding mechanism and/or an extension/retraction mechanism capable
of changing the length in the axial direction.
9. The maintenance equipment for an offshore wind turbine generator
according to claim 6, wherein the arm units include a plurality of
sets of grippers whose distance from each other in the axial
direction is changeable.
10. A maintenance method for maintaining a floating offshore wind
turbine generator with a crane ship, wherein the offshore wind
turbine generator is constructed using the maintenance equipment
according to claim 6 such that the tower member is joined to the
crane ship.
Description
TECHNICAL FIELD
[0001] The present invention relates to a construction method and
construction apparatus or a maintenance method and maintenance
equipment for an offshore wind turbine generator.
BACKGROUND ART
[0002] A conventional offshore wind turbine generator (hereinafter
referred to as an "offshore wind turbine") 1 employs, for example,
a monopile foundation shown in FIG. 11 or a fixed foundation shown
in FIG. 12.
[0003] Accordingly, when the offshore wind turbine 1 is
constructed, a construction method is employed in which, for
example, as shown in FIG. 13, a crane ship S used for construction
has its outriggers So lowered onto the seabed to alleviate rolling
of the hull due to ocean waves. Reference sign 2 in the drawing
denotes a tower member (tower) of the offshore wind turbine
generator 1, 3 denotes a nacelle, 4 denotes a rotor head, and 5
denotes a wind turbine blade.
[0004] On the other hand, if the construction is carried out using,
for example, a crane ship without the outriggers So, the effect of
rolling due to ocean waves must generally be reduced by selecting a
crane ship larger than those of typical weight, depending on the
size of the offshore wind turbine 1.
[0005] The above methods for constructing the offshore wind turbine
1, whose foundation is lowered onto the seabed, are means for
constructing the offshore wind turbine 1 without causing relative
misalignment by immobilizing the crane ship S or avoiding the
effect of rolling.
[0006] Construction methods and so on for construction of the
monopile or fixed offshore wind turbine 1 using the crane ship S
are disclosed in, for example, Patent Documents 1 to 3 below.
[0007] Patent Document 1:
[0008] Japanese Unexamined Patent Application, Publication No.
2006-37397
[0009] Patent Document 2: WO 2007/091042 A1
[0010] Patent Document 3: U.S. Patent Application, Publication No.
2006/0120809, specification
DISCLOSURE OF INVENTION
[0011] However, if an offshore wind turbine is installed in a deep
offshore area, it is difficult to lower a foundation of the
offshore wind turbine onto the seabed; typically, a floating
structure is employed.
[0012] To construct a floating offshore wind turbine, a method for
avoiding relative misalignment between the crane ship and the
offshore wind turbine due to, for example, rolling resulting from
ocean waves is essential. That is, without a method for avoiding
misalignment, it is extremely difficult to ensure the proper
positional relationship between components during, for example, an
overhead procedure for joining and mounting a nacelle at the top
end of a tower and an overhead procedure for joining and attaching
a hub and wind turbine blades to the nacelle at the top end of the
tower.
[0013] Against the above backdrop, for example, a floating offshore
wind turbine for installation in a deep sea area requires a
construction method and construction apparatus or a maintenance
method and maintenance equipment for an offshore wind turbine
generator that allow easy overhead assembly by avoiding
misalignment between components.
[0014] An object of the present invention, which has been made in
light of the above circumstances, is to provide a construction
method and construction apparatus or a maintenance method and
maintenance equipment for an offshore wind turbine generator that
allow safe and smooth construction of a floating offshore wind
turbine generator in deep sea.
[0015] To solve the above problem, the present invention employs
the following solutions.
[0016] A construction apparatus of the present invention for an
offshore wind turbine generator is a construction apparatus for
constructing a floating offshore wind turbine generator with a
crane ship, including a guide member attached to the crane ship in
a work position perpendicular thereto such that a bottom end of the
guide member is disposed under the sea and at least one pair of arm
units that include grippers capable of holding and releasing a
tower member divided into a plurality of segments in an axial
direction and that slide along the guide member.
[0017] Because the above construction apparatus for an offshore
wind turbine generator includes the guide member attached to the
crane ship in the work position perpendicular thereto such that the
bottom end of the guide member is disposed under the sea and at
least one pair of arm units that include the grippers capable of
holding and releasing the tower member divided into the plurality
of segments in the axial direction and that slide along the guide
member, the arm units can grip the tower member and join it to the
crane ship so that construction work can be carried out without
relative misalignment resulting from rolling due to ocean
waves.
[0018] In the above invention, the guide member is preferably
attached to the crane ship so as to be rotatable between a sailing
position parallel to the crane ship and the work position
perpendicular thereto. This prevents the guide member from
obstructing sailing of the crane ship.
[0019] In the above invention, the guide member preferably has an
axially sliding mechanism and/or an extension/retraction mechanism
capable of changing the length in the axial direction. This allows
the guide member to be lifted out of the sea or its length to be
decreased so that it does not obstruct sailing of the crane ship.
In addition, the optimum length and position of the guide member
for the work conditions can be set by operating the
extension/retraction mechanism depending on, for example, the
length of the tower member of the offshore wind turbine generator
to be constructed.
[0020] In the above invention, the arm units preferably include a
plurality of sets of grippers whose distance from each other in the
axial direction is changeable. This allows the tower member to be
reliably gripped even if its length is changed.
[0021] A construction method of the present invention for an
offshore wind turbine generator is a construction method, for
constructing a floating offshore wind turbine generator with a
crane ship, in which the offshore wind turbine generator is
constructed using the above-described construction apparatus such
that the tower member is joined to the crane ship.
[0022] In the above construction method for an offshore wind
turbine generator, because the offshore wind turbine generator is
constructed using the above-described construction apparatus such
that the tower member is joined to the crane ship, construction
work can be carried out without relative misalignment resulting
from rolling due to ocean waves, so that procedures such as
alignment are facilitated.
[0023] According to the present invention, for example, when a
floating offshore wind turbine for installation in a deep sea area
is constructed, it can readily be assembled overhead while avoiding
misalignment between components. That is, a floating offshore wind
turbine generator can be safely and smoothly constructed in deep
sea.
[0024] Maintenance equipment of the present invention for an
offshore wind turbine generator is maintenance equipment for
maintaining a floating offshore wind turbine generator with a crane
ship, including a guide member attached to the crane ship in a work
position perpendicular thereto such that a bottom end of the guide
member is disposed under the sea and at least one pair of arm units
that include grippers capable of holding and releasing a tower
member divided into a plurality of segments in an axial direction
and that slide along the guide member.
[0025] Because the above maintenance equipment for an offshore wind
turbine generator includes the guide member attached to the crane
ship in the work position perpendicular thereto such that the
bottom end of the guide member is disposed under the sea and at
least one pair of arm units that include the grippers capable of
holding and releasing the tower member divided into the plurality
of segments in the axial direction and that slide along the guide
member, the arm units can grip the tower member and join it to the
crane ship so that maintenance work can be carried out without
relative misalignment resulting from rolling due to ocean
waves.
[0026] In the above invention, the guide member is preferably
attached to the crane ship so as to be rotatable between a sailing
position parallel to the crane ship and the work position
perpendicular thereto. This prevents the guide member from
obstructing sailing of the crane ship.
[0027] In the above invention, the guide member preferably has an
axially sliding mechanism and/or an extension/retraction mechanism
capable of changing the length in the axial direction. This allows
the guide member to be lifted out of the sea or its length to be
decreased so that it does not obstruct sailing of the crane ship.
In addition, the optimum length and position of the guide member
for the work conditions can be set by operating the
extension/retraction mechanism depending on, for example, the
length of the tower member of the offshore wind turbine generator
to be maintained.
[0028] In the above invention, the arm units preferably include a
plurality of sets of grippers whose distance from each other in the
axial direction is changeable. This allows the tower member to be
reliably gripped even if its length is changed.
[0029] A maintenance method of the present invention for an
offshore wind turbine generator is a maintenance method, for
maintaining a floating offshore wind turbine generator with a crane
ship, in which the offshore wind turbine generator is constructed
using the above-described maintenance equipment such that the tower
member is joined to the crane ship.
[0030] In the above maintenance method for an offshore wind turbine
generator, because maintenance work is carried out using the
above-described maintenance equipment such that the tower member is
joined to the crane ship, the maintenance work can be carried out
without relative misalignment resulting from rolling due to ocean
waves, so that procedures such as alignment are facilitated.
[0031] According to the present invention, for example, when a
floating offshore wind turbine for installation in a deep sea area
is constructed or maintained, it can readily be assembled overhead
while avoiding misalignment between components. That is, a floating
offshore wind turbine generator can be safely and smoothly
constructed or maintained in deep sea.
[0032] Still other objects and advantages of the present invention
will become readily apparent to those skilled in the art from the
following detailed description, wherein the preferred embodiments
of the invention are shown and described, simply by way of
illustration of the best mode contemplated of carrying out the
invention. As will be realized, the invention is capable of other
and different embodiments, and its several details are capable of
modifications in various obvious aspects, all without departing
from the invention. Accordingly, the drawings and description
thereof are to be regarded as illustrative in nature, and not as
restrictive.
BRIEF DESCRIPTION OF DRAWINGS
[0033] The present invention is illustrated by way of example, and
not by limitation, in the figures of the accompanying drawings,
wherein elements having the same reference numeral designations
represent like elements throughout and wherein:
[0034] [FIG. 1] FIG. 1 is an explanatory diagram outlining an
embodiment of a construction method and construction apparatus for
an offshore wind turbine generator according to the present
invention.
[0035] [FIG. 2] FIG. 2 is a diagram showing an example of the
configuration of a tower member of the offshore wind turbine
generator shown in FIG. 1.
[0036] [FIG. 3] FIG. 3 is a diagram showing an example of the
configuration of the construction apparatus for the offshore wind
turbine generator, mounted on a crane ship shown in FIG. 1.
[0037] [FIG. 4] FIG. 4 is a diagram showing a first modification of
the relevant part of the construction apparatus in FIG. 3.
[0038] [FIG. 5] FIG. 5 is a diagram showing a second modification
of the relevant part of the construction apparatus in FIG. 3.
[0039] [FIG. 6] FIG. 6 is a diagram showing a specific example of
the configuration of an arm unit of the construction apparatus in
FIG. 3.
[0040] [FIG. 7] FIG. 7 is a diagram showing a first modification of
the relevant part of the arm unit in FIG. 6.
[0041] [FIG. 8] FIG. 8 is a diagram showing a second modification
of the relevant part of the arm unit in FIG. 6.
[0042] [FIG. 9] FIG. 9 is a diagram showing a third modification of
the relevant part of the arm unit in FIG. 6.
[0043] [FIG. 10] FIG. 10 is an explanatory diagram showing the
process of a construction method using the construction apparatus
for an offshore wind turbine according to the present
invention.
[0044] [FIG. 11] FIG. 11 is a diagram showing a monopile offshore
wind turbine generator.
[0045] [FIG. 12] FIG. 12 is a diagram showing a fixed offshore wind
turbine generator.
[0046] [FIG. 13] FIG. 13 is a diagram showing an example of a
method for constructing an offshore wind turbine generator using
outriggers of a crane ship as a conventional example.
EXPLANATION OF REFERENCE SIGNS
[0047] 10: offshore wind turbine generator (floating type) [0048]
20: tower member (tower) [0049] 21: ballast [0050] 22: undersea
tower section [0051] 23: oversea tower section [0052] 25: flange
[0053] 26: protrusion [0054] 50: construction apparatus [0055] 51,
51A, 51B: guide member [0056] 52: hydraulic cylinder [0057] 53:
sliding mechanism [0058] 55: extension/retraction mechanism [0059]
60: arm unit [0060] 61: slider [0061] 70, 70', 80, 90: gripper
[0062] 71: gripper body [0063] 73: holder [0064] 74: holding piece
[0065] 91: roller (rolling element) [0066] S: crane ship [0067] C:
anchoring cable
BEST MODE FOR CARRYING OUT THE INVENTION
[0068] An embodiment of a construction apparatus and construction
method for an offshore wind turbine generator according to the
present invention will now be described with reference to the
drawings.
[0069] Referring to FIG. 1, a floating offshore wind turbine
generator (hereinafter referred to as an "offshore wind turbine")
10 includes a nacelle 3, that slews depending on wind direction,
disposed at the top end of a tower member (tower) 20. A rotor head
4 is attached to the front end of the nacelle 3 so as to rotate
together with a plurality of wind turbine blades 5 protruding in
the radial direction. The nacelle 3 accommodates equipment such as
a gear box and a generator (not shown).
[0070] The illustrated offshore wind turbine 10 is a monopole
floating wind turbine having a ballast (floating body) 21 at the
bottom end of the tower member 20. This floating offshore wind
turbine 10 is disposed in deep sea so as to be floated by the
undersea tower buoyancy of the ballast 21 and is fixed to the
seabed with anchoring cables C. That is, the tower member 20 of the
floating offshore wind turbine 10 is not fixed to the seabed with a
foundation therebetween, but is fixed to the seabed with the
anchoring cables C so as to be floated in a desired sea area.
[0071] As shown in FIG. 2, for example, the tower member 20 of the
offshore wind turbine 10 is divided into a plurality of segments in
the axial direction. That is, the tower member 20 is divided into a
plurality of pillar segments in the axial direction that are
coupled together above the sea.
[0072] The illustrated tower member 20 includes the ballast 21,
which is the bottommost section; an undersea tower section 22
coupled to the top of the ballast 21 and located under the sea in a
normal installation state; and an oversea tower section 23 coupled
to the top of the undersea tower section 22 and exposed above the
sea in a normal installation state. The nacelle 3 is disposed at
the top end of the oversea tower section 23, which is the topmost
section of the tower member 20.
[0073] In FIG. 2, the ballast 21 is divided into n segments in the
axial direction, the undersea tower section 22 is divided into m
segments, and the oversea tower section 23 is divided into k
segments. The numbers of segments, namely, k, m, and n, are changed
as needed depending on various conditions that vary with the output
power of the offshore wind turbine 10 (e.g., the length of the wind
turbine blades 5).
[0074] In FIG. 2, reference sign 24 denotes anchor portions to
which ends of the anchoring cables C are fastened.
[0075] As shown in FIG. 1, for example, the floating offshore wind
turbine 10 described above is constructed (installed) at a
predetermined offshore position using a crane ship S.
[0076] The crane ship S is equipped with a construction apparatus
50, described below, for the offshore wind turbine 10. This
construction apparatus 50 grips the tower member 20 and joins it to
the crane ship S to allow construction work without relative
misalignment resulting from rolling due to ocean waves.
[0077] As shown in FIG. 3, for example, the construction apparatus
50 for the offshore wind turbine 10 includes a guide member 51
attached to the crane ship S in a work position substantially
perpendicular thereto such that the bottom end of the guide member
51 is disposed under the sea and at least one pair of arm units 60
that slide along the guide member 51. In the exemplary
configuration shown, a pair of top and bottom arm units 60 are
provided; they will be distinguished as a top arm 60A and a bottom
arm 60B in the description below as needed.
[0078] In addition, the above arm units 60 include grippers 70
capable of holding and releasing the tower member 20 divided into
the plurality of segments in the axial direction.
[0079] A main crane Km and a subcrane Ks are mounted on the
illustrated crane ship S. The main crane Km and the subcrane Ks are
used for loading/construction work, such as erecting and hoisting,
for the components of the offshore wind turbine 10, which are
separately loaded onto the crane ship S, including the nacelle 3,
the rotor head 4, the wind turbine blades 5, the ballast 21, the
undersea tower section 22, and the oversea tower section 23.
[0080] The above components of the offshore wind turbine 10 may be
loaded onto and transported by the crane ship S, or may be
transported by another ship and then transferred to the crane ship
S for construction using, for example, the main crane Km.
[0081] The guide member 51 is disposed, for example, at the front
of the crane ship S. This guide member 51 is an elongated rigid
member extending vertically in a predetermined work position, and
the bottom end thereof is disposed under the sea.
[0082] In addition, the above guide member 51 has a rotation
mechanism as described below. This rotation mechanism is an
apparatus capable of changing the attitude of the guide member 51
by rotating it about a fulcrum P between the work position of the
guide member 51, as indicated by the solid lines in FIG. 3, and the
sailing position of the guide member 51, as indicated by the
imaginary lines, by means of, for example, extension/retraction
operation of a hydraulic cylinder 52. That is, the guide member 51
with the rotation mechanism is attached to the crane ship S so as
to be rotatable between the sailing position, which is
substantially horizontal, i.e., parallel to the crane ship S, and
the work position, which is substantially vertical, so that the
guide member 51 does not obstruct sailing when the crane ship S
moves to a construction site.
[0083] Alternatively, the above rotation mechanism of the guide
member 51 may be replaced with, for example, a sliding mechanism of
a first modification shown in FIG. 4.
[0084] In this modification, a guide member 51A can be slid
vertically (see the arrow 54 in the drawing) by a sliding mechanism
53 fixed to and supported by the crane ship S. Specifically, the
sliding mechanism 53 can keep the bottom end of the guide member
51A lifted out of the sea during sailing of the crane ship S and
can keep the bottom end of the guide member 51A under the sea in
the normal work position. As a result, the bottom end of the guide
member 51A can be lifted out of the sea during sailing of the crane
ship S, or the length of the guide member 51A under the sea can be
decreased, whereas the bottom end of the guide member 51A can be
kept under the sea in the normal work position. In addition, the
optimum position of the guide member 51A for working can be set by
operating the sliding mechanism 53 depending on, for example, the
lengths of the components of the tower member 20, which vary with
the type of offshore wind turbine 10 to be constructed. The guide
member 51A with the sliding mechanism 53 may have the rotation
mechanism described above between the sliding mechanism 53 and the
crane ship S, particularly if the guide member 51A has a large
overall length.
[0085] Alternatively, the above rotation mechanism of the guide
member 51 may be replaced with, for example, an
extension/retraction mechanism of a second modification shown in
FIG. 5.
[0086] In this modification, the length of a guide member 51B in
the vertical direction (see the arrow 56 in the drawing) can be
changed by an extension/retraction mechanism 55 fixed to and
supported by the crane ship S. Specifically, the length of the
guide member 51B in the axial direction is decreased by operating
the extension/retraction mechanism 55 during sailing of the crane
ship S and is increased by operating the extension/retraction
mechanism 55 in the normal work position. As a result, the bottom
end of the guide member 51B can be lifted out of the sea during
sailing of the crane ship S, or the length of the guide member 51B
under the sea can be decreased, whereas the bottom end of the guide
member 51B can be kept under the sea in the normal work position.
In addition, the optimum length and position of the guide member
51B for working can be set by operating the extension/retraction
mechanism 55 depending on, for example, the lengths of the tower
components, which vary with the type of tower member 20 of the
offshore wind turbine 10 to be constructed.
[0087] The guide member 51B with the extension/retraction mechanism
55 may also be combined with at least one of the rotation mechanism
and the sliding mechanism 53 described above, particularly if the
guide member 51B has a large overall length. A configuration (not
shown) using gears, pulleys, wires, and so on by which the guide
member 51B can be moved as if it were rotated by a hydraulic
cylinder is also encompassed.
[0088] As shown in FIG. 6, for example, the arm units 60 include a
slider 61 that moves along the guide member 51 described above.
This slider 61 is slidable in the axial direction (longitudinal
direction) of the guide member 51, as indicated by the arrow 62 in
the drawing. At least one pair of top and bottom arm units 60 are
provided for one guide member 51.
[0089] The above arm units 60 include a plurality of sets of
grippers 70 capable of holding and releasing the tower member 20
divided into the plurality of segments in the axial direction. In
the exemplary configuration shown, the arm unit 60 includes two
sets of grippers 70 whose distance from each other in the axial
direction is changeable. In the description below, the individual
grippers 70 will be distinguished as needed by referring to the
grippers 70 located upward in the vertical direction as upper arm
parts 70A and to the grippers 70 located downward in the vertical
direction as lower arm parts 70B.
[0090] In the above exemplary configuration of the grippers 70,
specifically, a gripper body 71 is fixed to and supported by the
arm unit 60 so that they move together.
[0091] The gripper body 71 is provided with the upper arm parts 70A
and the lower arm parts 70B so that their distance from each other
in the axial direction is changeable by extension/retraction in the
axial direction of the guide member 51 (see the arrow 72 in the
drawing).
[0092] The upper arm parts 70A and the lower arm parts 70B are
formed of pairs of left and right L-shaped members and have pairs
of left and right holders 73 that follow the shapes of the ballast
21, the undersea tower section 22, and the oversea tower section
23, into which the tower member 20 is divided. The holders 73 are
supported so as to be swingable about pins 73a relative to the
L-shaped upper arm parts 70A and lower arm parts 70B.
[0093] The holders 73 each have a pair of holding pieces 75
attached thereto. The holding pieces 74 are supported so as to be
swingable about pins 74a. The holding pieces 74 have holding
surfaces 74b that are curved surfaces corresponding to the circular
cross section of the tower member 20, and antiskid pads such as
rubber pads are attached thereto as needed.
[0094] The above upper arm parts 70A and lower arm parts 70B are
opened and closed in the horizontal direction (see the arrows 75 in
the drawing), which is perpendicular to the vertical direction,
indicated by the arrow 72 in the drawing. As a result, when the
upper arm parts 70A and the lower arm parts 70B are closed, the
four holding pieces 74 are pressed against the outer
circumferential surface of a segment of the tower member 20 present
between the pairs of opposing left and right holders 73. Because
the pins 73a swingably support the holders 73 and the pins 74a
swingably support the holding pieces 74, the holding surfaces 74b
of the holding pieces 74 closely contact the ballast 21, the
undersea tower section 22, and the oversea tower section 23 while
absorbing the difference in outer diameter therebetween. The upper
arm parts 70A and the lower arm parts 70B can therefore reliably
grip the ballast 21, the undersea tower section 22, and the oversea
tower section 23.
[0095] When the upper arm parts 70A and the lower arm parts 70B
grip the tower member 20 of interest, they can be made to grip the
optimum positions thereof by adjusting, for example, the position
of the slider 61 and the distance between the upper arms 70A and
the lower arms 70B in the axial direction.
[0096] The movement of the slider 61, the change in the distance
between the upper arm parts 70A and the lower arm parts 70B in the
axial direction, and the opening/closing movement of the upper arm
parts 70A and the lower arm parts 70B may be accomplished by a
known actuation mechanism such as a hydraulic cylinder or a rack
and pinion.
[0097] In addition, the type of upper arm parts 70A and lower arm
parts 70B is not limited to the gripping method in which they are
opened and closed by sliding. As in a first modification shown in
FIG. 7, for example, grippers 70' supported so as to be swingable
about pins 76 may be used so that they are opened and closed. In
FIG. 7, the swingable holders 73, the holding pieces 74, and so on
are not shown.
[0098] In addition, FIG. 8 shows a second modification of the
grippers 70 or holding pieces 74 of the arm units 60. In this
method, grippers 80 hold grip portions, such as flanges 25,
provided on the segments of the tower member 20 described above,
rather than holding the outer circumferential portions thereof. In
this case, the grip portions are not limited to the flanges 25 for
coupling the segments of the tower member 20, but may be
protrusions such as pins.
[0099] In a third modification shown in FIG. 9, additionally,
protrusions 26 with a triangular cross section are provided on the
segments of the tower member 20, and rolling elements such as
rollers 91 are disposed between the protrusions 26 and grippers 90.
This configuration permits rotation of the tower member 20 relative
to the grippers 90 so that flange bolt holes of the segments of the
tower member 20 can readily be aligned.
[0100] Although the tower member 20 is rotatable in the
configuration shown, for example, the grippers 80 or 90 may be
rotatable relative to the arm units 60 so that they rotate together
with the gripped tower member 20.
[0101] The construction apparatus 50, thus configured, for the
offshore wind turbine 10 includes the guide member 51 attached to
the crane ship S in the work position substantially perpendicular
thereto such that the bottom end of the guide member 51 is disposed
under the sea and at least one pair of arm units 60 that include
the grippers 70 capable of holding and releasing the tower member
20 divided into the plurality of segments in the axial direction
and that slide along the guide member 51, so that the arm units 60
can grip the tower member 20, specifically, the segments of the
tower member 20 (the ballast 21, the undersea tower section 22, and
the oversea tower section 23), and join it to the crane ship S. As
a result, the crane ship S and the segments of the tower member 20
on the sea are made to roll substantially together by ocean waves,
so that construction work can be carried out without relative
misalignment therebetween resulting from rolling due to ocean
waves.
[0102] In this case, because the arm units 60 include the plurality
of sets of grippers 70 whose distance from each other in the axial
direction is changeable, they can reliably grip positions where a
good balance is achieved even if the length of the tower member 20
is changed.
[0103] A construction method for constructing the offshore wind
turbine 10 using the above construction apparatus 50 such that the
segments of the tower member 20 are joined to the crane ship S will
now be described with reference to the process chart shown in FIG.
10. In this case, the construction apparatus 50 shown in FIG. 3 has
the arm units 60 shown in FIG. 6, and the subcrane Ks of the crane
ship S is omitted from the drawing unless necessary.
[0104] In the first step, as the first segment of the tower member
20, the ballast 21 is hoisted by the main crane Km of the crane
ship S. At this time, if the ballast 21 is divided into a plurality
of segments, the bottommost segment is hoisted. The ballast 21 thus
hoisted is moved close to the guide member 51 by the main crane Km
and is gripped by the bottom arm 60B.
[0105] For illustration purposes, the bottommost segment gripped by
the bottom arm 60B in this step, namely, the ballast 21, is
referred to as a segment 20a, and the segments to be subsequently
coupled to the top of the segment 20a are referred to as segments
20b, 20c, . . . . That is, the plurality of tower segments
(segments) of the ballast 21, the undersea tower section 22, and
the oversea tower section 23 are described without being
distinguished unless necessary.
[0106] In the second step, the next segment 20b is mounted on and
joined to the ballast 21 (segment 20a). In this case, the segment
20b is the second bottommost ballast segment if the ballast 21 is
divided into a plurality of segments and is the bottommost segment
of the undersea tower section 22 if the ballast 21 is not
divided.
[0107] In the third step, the next segment 20c is mounted on and
joined to the topmost portion of the segment 20b and is gripped by
the top arm 60A.
[0108] In the fourth step, the segment 20a is released from the
bottom arm 60B and is freed. The top arm 60A then moves (slides)
downward along the guide member 51 while gripping the segment 20c.
In this case, the amount of downward movement is roughly equivalent
to the length of the single segment 20a, and the bottom arm 60B can
therefore grip the segment 20b after the movement is completed.
[0109] In the fifth step, the next segment 20d is mounted on and
joined to the topmost portion. The top arm 60A then releases the
segment 20c, moves upward, and grips the topmost segment 20d.
[0110] The process returns to the third step described above, and
the third to fifth steps, forming one cycle, are repeated by the
required number of cycles (the number of segments remaining). As a
result, the plurality of segments of the tower member 20 are
coupled together with the tower member 20 being gripped at two
upper positions by the top arm 60A and the bottom arm 60B. That is,
the construction apparatus 50 joins the tower member 20 to the
crane ship S, thus avoiding relative misalignment resulting from
rolling due to ocean waves.
[0111] In the final step, the assembly of the offshore wind turbine
10 is completed by attaching the nacelle 3 and the rotor head 4 to
the top of the completed tower member 20. At this time, for
example, attachment bolts and bolt holes can readily be aligned
because the crane ship S and the tower member 20 roll together
under the effect of ocean waves.
[0112] Afterwards, when the offshore wind turbine 10 is detached
from the crane ship S, the offshore wind turbine 10 is adjusted to
the position where its buoyancy and self weight are balanced by
moving the top arm 60A and the bottom arm 60B upward or downward
and is then released from the top arm 60A and the bottom arm
60B.
[0113] Thus, according to the present invention described above,
for example, when the floating offshore wind turbine 10 for
installation in a deep sea area is constructed, it can readily be
assembled overhead, namely, above the topmost portion of the tower
member 20, while avoiding misalignment between the components. That
is, the floating offshore wind turbine 10 can be safely and
smoothly constructed in deep sea.
[0114] Because relative displacement between the crane ship S and
the offshore wind turbine 10 can be avoided, the crane ship S
equipped with the above construction apparatus 50 is effective not
only in newly constructing the offshore wind turbine 10, but also
in maintenance work requiring a crane.
[0115] That is, the above construction apparatus 50 can be used as
maintenance equipment to carry out maintenance work, and the above
construction method can be used as a maintenance method in
maintenance. As for the details of the maintenance equipment and
the maintenance method, the construction and construction work in
the construction apparatus and construction method described above
may be construed as maintenance and maintenance work.
[0116] Thus, in the construction apparatus and construction method
and the maintenance method and the maintenance equipment of the
present invention, a structure such as that of the above
construction apparatus 50 is provided between the crane ship S and
the tower member 20 of the offshore wind turbine 10 near the tower
bottom (sea level) so that they can be joined together. As a
result, when the offshore wind turbine 10 is constructed, the above
structure can alleviate or avoid relative displacement between the
offshore wind turbine 10 and the crane ship S. The present
invention also encompasses joining, for example, the structure of
the offshore wind turbine 10 below the sea level to the hull of the
crane ship S before mounting the tower member 20 and the nacelle
3.
[0117] That is, in the present invention, the docking of the
offshore wind turbine 10 with the crane ship S allows them to move
in the same way in response to the effect of ocean waves, so that,
even though they cannot be completely fixed relative to the ground
or the seabed, relative displacement between the crane ship S and
the offshore wind turbine 10 can be avoided.
[0118] Accordingly, the offshore wind turbine 10 can be safely and
smoothly constructed in deep sea.
[0119] The present invention is not limited to the embodiment
described above and can also be used in, for example, maintenance;
modifications are permitted as needed without departing from the
spirit thereof.
[0120] It will be readily seen by one of ordinary skill in the art
that the present invention fulfils all of the objects set forth
above. After reading the foregoing specification, one of ordinary
skill in the art will be able to affect various changes,
substitutions of equivalents and various aspects of the invention
as broadly disclosed herein. It is therefore intended that the
protection granted hereon be limited only by definition contained
in the appended claims and equivalents thereof.
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